Posters Session II – C Nano MatEn 2015 - Nanotech for

Energy and Environment

Leaching of Nano-SiO2 from Municipal Solid Waste

E.T. Sakallıoglu,1 M. Bakırdoven,1 I. Temizel,1 C.S.Uyguner- Demirel,1 B. Demirel,1 N.K. Copty,1 T.T. Onay,1

T. Karanfil,2

1Bogazici University, Institute of Environmental Sciences, Bebek 34342 Istanbul, Turkey 2Clemson University, Department of Environmental Engineering and Earth Sciences, Anderson SC, USA

Abstract: The commercial use of nanomaterials has

significantly increased in recent years. However,

there is still limited information about the potential

impacts of nanomaterials on the environment within

the integrated solid waste management systems

(Boldrin et al., 2014). Nano SiO2 is used in numer-

ous commercial applications ranging from paint,

coating, fire resistant glassware, electronics, pharma-

ceuticals and UV protection (Marcoux et al., 2013).

The widespread synthesis and uses of SiO2 mean that

large volumes of this nanomaterial will ultimately

end up in landfills (Keller et al., 2013). The main

objective of this experimental work is to evaluate the

leaching potential and behavior of nano SiO2 within

the municipal solid waste-leachate matrix. Therefore,

batch experiments were conducted using fresh solid

waste samples obtained from a real municipal solid

waste (MSW) landfill located close to Istanbul, Tur-

key. The waste samples were spiked with different

concentrations of SiO2 in batch reactors. During the

experiments, two different pH values were consid-

ered, namely basic 8-9 and acidic 5-6. The effect of

ionic strength on the leaching characteristics of SiO2

was also evaluated. Leachate samples were regularly

collected over a three-day period and analyzed for

pH, conductivity, particle size distribution and total

Si concentration. A kinetic model was also devel-

oped to evaluate the deposition and detachment of

SiO2 onto the solid surface.

Keywords: Landfill, leaching, municipal solid waste,

nanomaterial, SiO2

References:

Boldrin, A., Hansen, S.F., Baun, A., Hartmann,

N.I.B., Astrup, T.F. (2014) Environmental exposure

assessment framework for nanoparticles in solid

waste, J. Nanopart. Res., 16, 2394.

Keller, A.A., McFerran, S., Lazareva, A., Suh, S.

(2013) Global life cycle releases of engineered na-

nomaterials, J. Nanopart. Res., 15, 1692.

Marcoux, M.A., Matias. M., Olivier, F., Keck, G.

(2013) Review and prospect of emerging contami-

nants in waste –key issues and challenges linked to

their presence in waste treatment schemes: general

aspects and focus on nanoparticles, Waste Manage.,

33, 2147-2156.

The Role of Al2O3 and SiO2 Nanoparticles on the Cycleability of

Li-Air Batteries with TEGDME-PEO/LiPF6 Electrolytes A.Akbulut Uludağ1, M. Tokur2, H. Algul2, T. Cetinkaya2, M. Uysal2, H. Akbulut2

1 : Sakarya University, Dept. of Environmental Engineering, Esentepe Campus, 54187, Sakarya, Turkey 2: Sakarya University, Metallurgical & Materials Engineering Dept., Esentepe Campus, 54187, Sakarya, Turkey

Abstract: Rechargeable lithium-air (Li-air) batteries

have the potential to provide gravimetric energy three

to five times greater than that of conventional Li-ion

batteries. Identifying the appropriate electrolyte is

one prerequisite for the application of Li-air batter-

ies1. In this work, an ether based electrolyte contain-

ing TEGDME/LiPF6 was optimized, which possessed

low viscosity and high ionic conductivity, under dry

argon atmosphere in a glove box. In order to prevent

air breathing cathode clogging by lithium oxide and

provide stability of Li metal anode, an extensive

work was carried out to provide most functional pol-

ymeric additives and Poly(ethylene oxide) (PEO)

was found one of the most effective polymers as re-

cently stated by different a work2. Two different in-

organic fillers were chosen to add into the electrolyte

to prevent conductivity decrease and provide stability

of the air cell. Nano Al2O3 and SiO2 were incorpo-

rated into TEGDME-PEO/LiPF6 composite homoge-

nously. Both PEO and nano ceramic powders were

thought to promote the dissolution of lithium perox-

ide precipitates formed in course of discharge process

and protect the anode against to the corrosion. Gra-

phene/-MnO2 nanocomposite air breathing structure

was used as cathode. In the carbon cathode materials,

Graphene nanosheets (GNS) have been reported as

ideal cathode materials for Li-O2 batteries because of

their unique morphology and structure that provide

both diffusion channels for O2 and active sites for

cathode reactions. On the other hand, -MnO2 cata-

lysts is helpful to increase the reversibility of the lith-

ium-oxygen interactions due to hollandite type crystal

structure of MnO2 consists 2x2 tunnels. A lithium

disk was used as anode while glass fiber was used as

the separator in ECC-Air test cell. The cells were

cyclically tested using 0.1 mA/cm2 current density

over a voltage range of 2.15-4.25 V. Electrochemical

impedance spectroscopy (EIS) measurements was

applied to investigate the effect of the polymeric and

inorganic additives on the resistivity of the electro-

lyte. Results revealed that nanocomposite electrolyte

structures provided not only good discharge capacity

Keywords: Li-air battery, cycle life, stability,

TEGDME, Al2O3 and SiO2 additives, nanocomposite

electrolyte, PEO,

but also excellent stability of the Li-air cells. As can

be seen in Fig.1, excellent cycleability was obtained

by using the nanocomposite electrolytes with both

organic (PEO) and inorganic (Al2O3, SiO2) additions.

Up to After the electrochemical cycling test, the cy-

cles no significant capacity fade was detected and the

ongoing studies show the air cell will show excellent

stability with increasing cycle number. Morphologies

of the cathodes were analyzed using scanning elec-

tron microscopy, X-ray diffraction analysis, and Ra-

man spectroscopy to determine the occurrence of

reaction products.

Fig. 1. Time-voltage behavior of TEGDME-PEO

/LiPF6/1 wt. % Al2O3 nanocomposite electrolyte.

Fig. 1. Capacity-voltage behavior of TEGDME-PEO

/LiPF6/1 wt. % Al2O3 nanocomposite electrolyte

References:

1. G. Girishkumar, B. McCloskey , A. C. Luntz , S.

Swanson and W. Wilcke, Lithium−Air Battery:

Promise and Challenges, J. Phys. Chem. Lett., 2010,

1 (14), pp 2193–2203

2. Chibueze V. Amanchukwu, Jonathon R. Harding,

Yang Shao-Horn, and Paula T. Hammond, Under-

standing the chemical stability of polymers for lithi-

um-air batteries, Chem. Mater., Just Accepted Manu-

script, DOI: 10.1021/cm5040003, 2014.

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Transparent Hydrophobic Nanolayers on ETFESiOx Sub-strates for Solar Cells Encapsulation

G. Rossi,

* P. Scarfato, L. Incarnato

Department of Industrial Engineering, University of Salerno, Fisciano (SA), ITALY

Abstract: Polymer materials are recently emerging

as an interesting alternative to glass as encapsualnt

and coating materials for preserving solar cells from

the atmospheric degradation agents, due to their flex-

ibility, affordable cost and transparency. However,

they present the disadvantage of low barrier proper-

ties. Hydrophobic and more in general liquid barrier

properties may significantly improve the protection

guaranteed by the encapsulant materials, addressing

issues like corrosion effects and loss of electrical

performance and also adding self-cleaning properties

to the surface thanks to the roll-off effect consequent

to the hydrophobic behavior. Although several meth-

ods are reported in literature (Ling. Et al., 2009,

Karunakaran et al., 2011) for obtaining hydrophobi-

city on substrates applicable to the solar cells sector,

these methods are likely to be expensive and difficult

to be implemented at industrial level because they are

complex multi-step processes, including high temper-

ature steps. In a previous work (Rossi et al., 2014) we

developed a single step method to synthetise at room

temperature a transparent hydrophobic self-

assembled monolayer (SAM) chemisorbed on Poly-

ethylene terephthalate (PET-SiOx) substrate, a stand-

ard coating for PV cells. In the present study, this

method was applied on the bilayer Ethylene tetrafluo-

roethylene – Silicon Oxide (ETFE-SiOx), usually

employed as frontsheet for solar cells, experimenting

also a new precursor molecule. The SAM deposition

was performed in anhydrous toluene using 1% con-

centration of two different precursor molecules:

1H,1H,2H,2H-per-fluorodecyltrichlorosilane (CFAS)

and 1H,1H,2H,2H perfluorodecyltriethoxysilane.

(EFAS). FTIR (Fourier Transform Infrared Spectros-

copy) measurements carried out on the uncoated and

nanocoated samples confirmed the successful deposi-

tion of the SAM Nanolayer on ETFESiOx substrate.

The hydrophobic properties characterization of the

nanocoated samples indicated that the surface sub-

strate was changed from hydrophilic to hydrophobic

for all the nanocoated systems. The oleophobic prop-

erties were also significantly enhanced by the SAM

deposition, particularly for the CFAS nanocoated

system that was modified from oleophilic to oleo-

phobic (oil CA: 92°). Furthermore, the optical prop-

erties assessment revealed that only a slight transpar-

ency decrease occurred for CFAS nanocoated sam-

ple, while no substantial reduction of transmittance

was detected for the EFAS nanocoated system.

Concluding, the adopted SAM procedure can repre-

sent an effective route for obtaining nanocoated pol-

ymer materials with enhanced barrier properties at

sustainable costs, suitable to extend the lifetime of

encapsulated solar cells.

Keywords: Hydrophobic Coatings, Oleophobic Coat-

ings, Self-Assembly of Monolayers, FluoroAl-

kylsilanes, Solar Cells, Ethylene tetrafluoroethylene –

Silicon Oxide.

Figure 1: H2O and oil Average static contact angle on

the SiOx side for samples: ETFE-SiOx uncoated and

nanocoated with SAM of CFAS and EFAS.

0

20

40

60

80

100

120

ETFESiOx CFAS EFAS

Water

Oil

References:

Ling, X.Y., Phang, I. Y., Vancso, G.J., Huskens, J.,

Reinhoudt, D.N. (2009) Stable and Transparent Su-

perhydrophobic Nanoparticle Films, Langmuir, 25,

3260–3263.

Karunakaran, R.G., Lu, C., Zhang Z., Yang, S.

(2011), Transparent Superhydrophobic Surfaces from

the Coassembly of Nanoparticles (≤100 nm), Lang-

muir, 27, 4594–4602.

Rossi, G., Altavilla, C., Scarfato, P., Ciambelli, P.,

Incarnato L. (2014), Deposition of transparent and

flexible nanolayer barrier on standard coating materi-

als for photovoltaic devices, Surf. Coat. Technol.,

239, 200-105.

Photovoltaic Response of Non-Toxic CuInS2 Quantum Dot based Conducting Polymer Composite Films

I. Singh,1,2,* J. Singh,2 A. Kumari,2 P.K. Rao,2 P.K. Bhatnagar2

1University of Delhi, Department of Electronics, SGTB Khalsa College, Delhi, India 2University of Delhi South Campus, Department of Electronic Science, New Delhi, India

Abstract: I-III-VI ternary compound non-toxic quan-

tum dots (QDs) have recently attracted the scientific

community because of their attractive electrical and

optical properties (Allen et al.; 2008). CuInS2 (CIS)

is the most extensively studied form among various I-

III-VI ternary compositions. It is environment friend-

ly, has a small direct band gap of 1.5 eV (which is

nearly the optimum band gap for a single junction

photovoltaic device), high absorption coefficient

(>105 cm-1), high photoconductivity and possesses

long term electronic stability (Lewerenz et al.;

2004). The Bohr exciton radius for CIS QDs is ~4

nm hence nanopaticles having size less than ~ 8 nm

can show quantum confinement effects (Czekelius et

al.; 1999). In the present work, we have studied the

optical and electrical properties of poly(3-

hexylthiophene) (P3HT) and CIS QDs based compo-

site films. It is found that the absorption spectrum of

the polymer film becomes broader by the incorpora-

tion of CIS QDs. The photoluminescence of the

P3HT in the composite is also found to be quenched

indicating an efficient charge transfer from polymer

to the QDs. The electrical characterization of the

P3HT:CIS composite film showed an improvement in

the current density by more than an order of magni-

tude as compared with that of P3HT only device.

Keywords: conducting polymer, non toxic quantum

dots, photovoltaic applications, thin films.

Figure 1: Energy band diagram of conducting poly-

mer (P3HT): CIS QD composite structure

References:

Allen, P.M., Bawendi, M.G. (2008) Ternary I-III-VI

quantum dots luminescent in the red to infrared, J.

Am. Chem. Soc.,130, 9240-9241.

Lewerenz, H.J. (2004) Development of Copper Indi-

um disulfide into a solar material, Sol. Energy Mater.

Sol. Cells, 83, 395-407.

Czekelius, C., Hilgendorff, M., Spanhel, L., Bodja,

I., Lerch, M., Miller, G., Bloeck, U., Su, D.S., Gier-

sig, M. (1999) A simple colloidal route to nanocrys-

talline ZnO/CuInS2 bilayers, Adv. Mater., 11, 643-

646.

Benefits of a compact TiO2 layer for the elaboration of transparent TiO2 nanotubes array on conducting glass

A. Krumpmann, A. Decroly

Department of Materials Science, Faculty of Engineering, University of Mons, Mons, Belgium

Abstract: Titania nanotubes obtained by the ano-

dization method have received much attention due to

numerous possible fields of application including

sensors, photocatalysis or photovoltaics. Anodization

is classically performed on Ti foils but for photovol-

taic applications, the TiO2 nanotube array layer has to

be elaborated on a transparent substrate such as

transparent conducting oxide (TCO) coated glass.

Therefore a metallic Ti layer is sputtered on TCO

and then anodized to be converted to a transparent

TiO2 nanotube array (TNA) layer (figure 1). We de-

scribe the impact of introducing an additional com-

pact TiO2 layer under the metallic Ti layer during the

sputtering deposition and compare morphological

and optical properties of titania nanotubes films made

with and without this intermediate compact layer.

These results show considerable improvements in the

TNA layer macroscopic homogeneity when a com-

pact layer is used. They are attributed to the limita-

tion of an undesirable reaction of oxygen evolution

that takes place preferentially at the TCO-electrolyte

interface during anodization, causing a destructu-

ration of the TNA layer. Thus, using a TiO2 compact

layer allows a better control of the anodization pro-

cess and the transparency of the TNA layer in the

visible range is also increased. Furthermore, for solar

cell applications, the compact layer can act as a

blocking layer which is a common way to reduce

charge recombination.

Keywords: Titanium dioxide, thin films, nanotubes,

1-D nanostructures, anodization, solar cell applica-

tions.

Figure 1: Scanning electron microscopy image of a

1 µm thick TiO2 nanotube array film on TCO glass

with an intermediate compact TiO2 layer of approx-

imately 50 nm.

Study of LiFePO4 thin films as Li-ion battery cathode by in-situ

electrochemical atomic force microscopy in aqueous electrolyte

J. X. Wu, G. Y. Shang*

School of Physics, Beihang University, Beijing 100191, P. R. China

Abstract:

Lithium-ion (Li-ion) batteries have been widely used

as power sources for portable and mobile applica-

tions (Armand et al., 2008). In order to prolong bat-

tery life, it is important to study the mechanisms that

make battery capacity reduce with aging. Published

results have show that morphological changes occur

in aged cathodes. In this study, in-situ electrochemi-

cal atomic force microscopy (EC-AFM) that is com-

bined atomic force microscopy with electrochemical

methods was used to investigate morphological

changes of LiFePO4 thin film electrodes during

charge and discharge processes in real time under

aqueous environment (Demirocak et al., 2014;

Ramdon et al., 2014). LiFePO4 thin films were pre-

pared by depositing them on Au/Si substrate using

radio frequency magnetron sputtering deposition

method. The films were firstly characterized by X-ray

diffraction, and results showed that them were com-

posed of LiFePO4 phase with olivine structure. The

SEM and AFM results show that the average size of

particle was ~100 nm. The electrochemical perfor-

mance of the film electrodes in Li2SO4 aqueous elec-

trolyte was investigated by cyclic voltammetry. The

lithium ion diffusion coefficient of the film electrode

was estimated to be 2.31×10-7 cm2s-1, which is larger

than that of LiFePO4 powder of 5.53×10-8. The de-

crease and increase in the size of the LiFePO4 parti-

cles during charge and discharge were directly ob-

served by EC-AFM, and relevant mechanism is dis-

cussed.

Figure 1: EC-AFM images show that the changes in

the size of the LiFePO4 film electrode during charge

and discharge in the aqueous electrolyte.

References:

Armand, M.; Tarascon, J-M. (2008), Building better

batteries, Nature, 451, 652-657.

Demirocak, D. E.; Bhushan, B. (2014), In situ atomic

force microscopy analysis of morphology and parti-

cle size changes in Lithium Iron Phosphate cathode

during discharge, J. Colloid Interface Sci., 423, 151-

157.

Ramdon, S.; Bhushan, B.; Nagpure, S. C. (2014), In

situ electrochemical studies of lithium-ion battery

cathodes using atomic force microscopy. J. Power

Sources, 249, 373-384.

Textured fabrication of CdS/CdTe thin film PV cell with back contacts

Murugaiya Sridar Ilango1, 2, Sheela K Ramasesha1,*

1Indian Institute of Science, Divecha Centre for Climate Change, Bangalore, Karnataka, India 2Department of Physics, Jain University, Bangalore, Karnataka, India

*sheela@caos.iisc.ernet.in

Abstract: The basic function of a Solar cell is to

absorb sunlight and convert light energy into

electricity. The energy obtained is carbon free

renewable source of energy without any moving part.

The principle of solar cell came into lights when the

great scientists Chapin, Pearson, and Fuller prepared

a photovoltaic effect using poly-Si in 1954. Since

silicon semiconductor technology was so widely

studied, for more than 40 years solar cells were

fabricated using silicon crystals . As a replacement for

silicon, materials which can be used are amorphous

silicon, CdTe, Cu (In, Ga) Se2, InP, CdSe and GaAs.

Thin film solar cells are considered to be large area

diodes, to increase the absorption of light and reduce

the cost of fabrication. Electron-hole pairs are

generated by the absorbed photons, the electric energy

is formed when the excited carrier is swept across the

potential field. The voltage generated during the

separation of opposite charge helps in driving the

current through external electric circuit. In a

CdS/CdTe based solar cell the potential field or the

depletion layer is formed at the interface of the CdS

and CdTe layers. In this paper CdS is the window

layer which has a wide band gap of 2.45 eV which

allows most of the light to the absorber layer CdTe

with a band gap of 1.45 eV. Photons from the sunlight

are absorbed only when the energy is higher than the

band gap of the absorber layer. Thin film Solar cells

have a record efficiency of 19.6%, and commercially

available CdTe PV panels of 12% (Green, et al.,

2013). The loss due to reflection has limited all types

of solar cells to a great extent. Hence, one method of

trapping the light for more absorption is through nano-

texturing of junction area. In commercial thin-film

CdTe solar panels 4% of its energy is already reflected

in the glass-air interface of the modules (Kaminski, et

al., 2014). Nanostructuring of silicon has produced

extensive research in solar cell application because of

its low reflectance and enhanced light trapping

technique (Oelhafen, et al., 2005). Along with the

texturing of junction area, the concept of back contact

is taken into account (Figure 1). As the front contact

in a solar cell transmits only 50% of the solar radiation

(Fan, et al., 2009), back contact research started after

the publication of R.J Schwartz in 1975 as a substitute

for cells which has front and rear contacts. The metal

grids with narrow, closely packed metal lines can

reduce series resistance (Dean, et al., 1975) but

increases blockage of sunlight (by reflecting). As the

front and rear contacts are placed at the rear surface,

increases the packaging density of the panel and also

gives raise to performance gain (Kerschaver, et al.,

2006). So the performance of back contact solar cell

is to be tested along with the increased junction area

by texturing the interface surface.

Keywords: textured solar cell, back contact,

CdS/CdTe, nanowall design, thin flim PV.

Figure 1: SEM image of Nano wall structure (Surface

morphology)

References:

Dean R. H., Napoli L. S. and Liu S. G. (1975) Silicon solar

cells for highly concentrated sunlight, RCA Review, 36, 324-335.

Fan Zhiyong [et al.] (2009)Three dimensional nanopillar

array photovoltaics on low cost and flexible substrates,

nature materials, 8, 648-653.

Green Martin A. [et al.] (2013) Solar cell efficiency tables

(version 42), Progress in Photovoltaics: Research and

Applications, 21, 827-837.

Kaminski P. M., Lisco F. and Walls J. M. Multilayer (2014)

Broadband Antireflective Coatings for More Efficient Thin

Film CdTe Solar Cells, IEEE Journal of Photovoltaics, 4,

452-456.

Kerschaver Emmanuel Van and Beaucarne Guy

(2006)Back-contact Solar Cells: A Review, Progress in

Photovoltaics: Research and Applications, 14,107-123.

Oelhafen P. and Schuler A. (2005) Nanostructured materials for solar energy conversion, Solar Energy, 79,110-121.

Nonradiative  Electron  and  Hole  Relaxation  Dynamics      in  Organometallic  Halide  Perovskites

M.E. Madjet,1 F. El-Mellouhi,1, , G. Berdiyorov1, S. Ashhab1 A. Akimov2 and S. Kais1

1Qatar Environment & Energy Research Institute, Qatar Foundation, PO Box 5825, Doha, Qatar 2Department of Chemistry, University of Southern California, Los Angeles, CA 90089

Abstract: Hybrid organic-inorganic perovskites, such as methylammonium (MA) lead iodide (CH3NH3PbI3 or MAPbI3), are promising new ab-sorber materials for solar energy applications that have attracted significant interest in the last few years. Solar conversion efficiencies of more than 19% have been reported for these materials [1]. This high efficiency is mainly due the long diffusion lengths of charge carriers, low sensitivity to defects and high mobility of charge carriers. However, many fundamental processes related to the photophysics of these materials remain not fully understood. The excitation of electrons from the valence band to conduction band results in the formation of hot elec-trons and holes, both of which lose most of their en-ergy by cooling down to the band edges. Extracting hot carriers before they thermalize towards the re-combination would lead to higher efficiency. Conse-quently, simulating the relaxation dynamics of pho-toexcited charge carriers is of great importance for further optimization of photovoltaic devices. In order to understand in more detail the process of charge carrier dynamics in peroveskite materials, a theoretical description based on time-domain meth-ods is required to enable shedding light on recent experimental finding on electron and hole relaxation dynamics [2] and also to guide future experimental investigations. A mixed quantum-classical approach based on trajectory surface hopping is used to de-scribe the dynamics of hot charge carriers. In this approach, the electrons are described quantum me-chanically by solving the Schroedinger equation and the nuclear degrees of freedom are propagated by independent classical trajectories, which are com-puted by solving the classical Newton’s equations. In this contribution, we address the non-radiative relaxation process of electrons and holes in organo-metallic perovskite CH3NH3PbI3 when electrons are promoted to the conduction band from the valence-band. We perform nonadiabatic molecular dynamics simulations using the combination of the PYthon eXtension for Ab Initio Dynamics [3] package for quantum dynamics simulations interfaced with the Quantum Espresso electronic structure code. Our aim is to get a fundamental understanding of the intra-band relaxation process of hot electrons (holes) to the minimum (maximum) of the conduction (valence) band and how these processes are affected by perov-skite composition and structure. Results on the per-

ovskite materials CH3NH3PbI3, CH3NH3PbBr3, CH3NH3PbCl3, CH3NH3PbI3-xBrx and CH3NH3PbI3-

xClx will be presented. The electron relaxation time values obtained from our simulation for CH3NH3PbI3 are in good agree-ment with the experimental data reported in Ref. [2]. We also found that halogen-mixing CH3NH3PbI3-xClx results in slowing down the elec-tron and hole relaxation process, suggesting a longer life time in Cl-doped systems. Keywords: Photovoltaic, perovskite, electron/hole transport, nonradiative carriers relaxation, nonadi-abatic dynamics, surface hopping.

References:

[1] National Renewable Energy Laboratory, Best Research-Cell Efficiencies; www.nrel.gov/ncpv/images/efficiency chart.jpg

[2] Hung-Yu Hsu et al, Angew.Chem. Int. Ed. 53, 1 (2014).

[3] A.V. Akimov and O.V. Prezhdo, J. Chem. Theory Comput. 9, 4959 (2013).

C-Nanotube Based Infrared Thermo-Voltaic Cells and Detectors

T.Hosseini, N.Yavarishad and N. Kouklin

Dept. of Electrical Engineering, Univ. of Wisconsin-Milwaukee,P.O. Box 413 Milwaukee, WI, 53201, USA

Abstract: Sun radiation remains a key renewable energy source, with ~40% of its energy falling into the infrared part of the EM spectrum. This low grade energy, while available is thinly stretched over a relatively broad spectral win-dow of ~ 0.7-3 μm. For a p-n junction based photovoltaic (PV) solar cell, a maximum vol-tage is limited by Voc≅ Eg/e, where e stands for the unit charge. For ideal cells, the conversion efficiency is to scale linearly with Eg given by 𝜒𝜒 (𝜆𝜆)~ 1

𝜆𝜆~ 𝐸𝐸𝑔𝑔 .[1] As the fabrication and

deployment costs are to be on par with those of existing PV systems, IR-PV cells that inherit conventional design are to demonstrate at least order of magnitude lower efficiency-to-cost ra-tio. While several concepts were offered to harvest IR-sun radiation including antenna ar-rays and quantum dots, with their spectrally-broad absorption spectrum and the fabrication cost that has fallen precipitously, single-walled carbon nanotubes can pave a way to the devel-opment of indirect-type, cost-efficient photo-thermo-voltaic (PTV) cells.

Herein, we engineer and test two-terminal car-bon nanotube photocells for the purpose of infrared photo-thermo-electric energy conver-sion and sensing. The photo-voltage and nonze-ro conversion efficiency were found to appear only for off-center illumination which can be explained within photo-generated heat flow model and not the contact effects. [2] Under incident optical powers of ca. 450 mW, the equivalent short-circuit current, ISC, and open-circuit voltage, VOC, stood at ca. 0.2 uA and ca. 0.5 mV, respectively. The cell prototypes yielded ~ 30 nW of electrical power that typical-ly followed non-monotonic dependence on the incident light power given by Pout max~ β

inP , where 08.1=β . As the PTV cell can also uti-lized as IR-photosensor, its transient response was probed by carrying out off/on photocurrent tests at varied temperatures: 123, 253 & 300 0K. The photo-current, Iph decayed with

-1.8x10-7 -9.0x10-8 0.0

0.0

2.0x10-8

4.0x10-8

0.0 0.3

-0.2

0.0

dark 49 mW 186 mW 329 mW 453 mW

Cur

rent

, uA

Voltage, mV

Gen

erat

ed P

ower

, WCurrent, A

time as single exponential Iph ~ 1 − 𝑒𝑒−𝑡𝑡/𝜏𝜏 and the characteristic decay constant,τ was found to change linearly with I-1

dark confirming that the transient respose is controlled by device circui-try and not heating/cooling processes. The con-cept might enable engineering and implementa-tion of the carbon nanotube based PVT devices for application in heat recycling and self-powered infrared detectors. Keywords: infared, carbon, nanotubes, photovoltaic, sensors, cell.

Figure 1: Showing power vs. current characteristic of the PTV cell obtained at RT and incident power of ~ 450 mW. The inset shows I-Vs for different

References:

[1] S.M.Sze, “Semiconductor Devices”, J.Willey and Sons, 2nd edition (2002) [2] T. Hosseini, M. Omari. and N. Kouklin, Electr. Dev. Letters, 34 , 7 , 924-926 (2013)

Natural  Biodefensive  Nanoparticles  for  Pest  Control  in  Soy  Culture  

A.L. Santos,1* V. Zucolotto,1,2 B.T.R. Rhein,1 I. Pezzopane,1 G.Rosa1

1Nanomed Inc., São Carlos, Brazil 2University of São Paulo, Laboratory of Nanomedicine and Nanotoxicity, São Carlos, Brazil

Abstract: Nanomed Inc. has been developing a new methods for natural compounds controlled delivery system. A polymeric nanoparticle obtained via sol-vent evaporation is a new approach to delivery a nat-ural and reactive compound to improve the treatment in soy culture, the most important culture in Brazil. This is a bioactivity essential oil against insects and other pests, flavoring agent used in cosmetic and food products however it was previously reported to have a skin- sensitizing ability and to cause allergic reactions (ATSUMI; FUJISAWA; TONOSAKI, 2005; MURRAY B. ISMAN, 2006). In spite of huge bioactivity, its reactivity and volatility reduce the action time. So, a controlled delivery system was developed, changing the surface area which may influence its toxicity. The nanoparticles cytotoxicity was evaluated in L929 fibroblasts, against a negative control and literature. The enhancement of the natural active by encapsula-tion was able to protect it from oxidative degrada-tion, and improve their fungicidal activity (GARG; SINGH, 2011). We observe that these nanoparticles showed a similar behavior even in different delivery system (polymer). However with the concentration increase, there is the decrease of toxicity, with the higher viability in fibroblasts. Based on the different concetrations stud-ies, it is possible to conclude that the cytotocity is not dose dependent. However, one notice the increase in the cellular apoptosis as the nanoparticle size de-creases. So, the nanotoxicity is directly linked to the size of nanoparticle, and not related to the essential oil concentration. Keywords: biodefensive, polymeric nanoparticles, natural-based material, cytotoxity, pest control, soy culture, agribusiness applications.

Figure 1: Figure of natural compound nanoparticles cytotoxicity in a different controlled delivery sys-tem, at 0.1 ppm concentrations. Samples: 1- PLA- natural compound 0.5%; 2- PCL- natural compound 1%; 3- PLA- natural compound 1%.

References:

ATSUMI, T.; FUJISAWA, S.; TONOSAKI, K. A comparative study of the antioxidant/prooxidant activities of eugenol and isoeugenol with various concentrations and oxidation conditions. Toxicology in vitro, v. 19, n. 8, p. 1025–33, dez. 2005.

GARG, A; SINGH, S. Enhancement in antifungal activity of eugenol in immunosuppressed rats through lipid nanocarriers. Colloids and surfaces. B, Biointerfaces, v. 87, n. 2, p. 280–8, 15 out. 2011.

MURRAY B. ISMAN, C. M. M. Pesticides based on plant essential oils: from traditional practice to commercialization. In: CARPINELLA, R. AND (Ed.). . Naturally Occurring Bioactive Compounds. [s.l.] Elsevier, 2006. p. 29–44.

Sol-Gel Production and Electrochemical Characterization of

Free-Standing Metal Oxide/MWCNT Nanocomposite Anodes for

Li-Ion Batteries

H. Köse, Ş. Karaal, A. O. Aydın, H. Akbulut

Sakarya University, 54187, Sakarya, Turkey

Abstract: Lithium ion batteries (LIBs) are one of the

most promising candidates for electrochemical ener-

gy conversion and storage devices, in the scientific

and industrial fields, with one of the best energy den-

sities (Wang et al.; 2006). Zinc and tin dioxide based

materials are being used as active anode materials for

rechargeable lithium batteries, because the theoretical

capacity of ZnO (978 mAhg-1

) and SnO2 (1491

mAhg-1

) has been estimated to be superior to that of

graphite (372 mAhg−1

) (Guler et al.; 2014, Ning et

al.; 2008). High capacity anodes such as zinc and tin

based usually suffer severe capacity fading, because

of the quick aggregation of metal particles and the

huge volume expansion during Li+ inser-

tion/extraction cycles (Huang et al.; 2011). To pre-

vent the pulverization of the anodes and electrical

detachment of active materials, MWCNT buckypaper

substrates are considered as a buffer material during

the battery applications (Guler et al.; 2014). In this

work, ZnO/MWCNT and SnO2/MWCNT buckypa-

per nanocomposite films were prepared as free-

standing anode materials by sol–gel spin coating.

Structural properties and electrochemical perfor-

mances of metal oxides/MWCNT nanocomposite

anodes were investigated and compared. As can be

seen from Figure 1, it was aimed to accommodate the

stresses arisen from the volume increase during

charging process by using highly porous MWCNT

network that coated with a thin layer of the metal

oxides (MO). The structural properties of free-

standing buckypaper composite film anodes were

characterized by FEG-SEM (Field Emission Gun -

Scanning Electron microscopy), TEM (Transmission

Electron Microscopy), EDS (Energy Dispersive X-

ray Spectroscopy) and XRD (X-ray Diffraction)

tehcniques. Electrochemical performance tests, CV

(Cyclic Voltammetry) and EIS (Electrochemical

Impedance Spectroscopy) analyses of free-standing

anodes of CR2016 type Li-ion batteries were also

performed. The cells were charged and discharged at

25 °C between fixed voltage limits (2.5 V to 0.2 V).

Keywords: Li-ion battery applications, metal ox-

ide/MWCNT nanocomposite anodes, sol-gel synthe-

sis, spin coating method, structural and electrochemi-

cal characterization.

Figure 1: The illustration of the production of free-

standing Metal Oxide/MWCNT anodes.

References:

Guler, M.O., Cetinkaya, T., Tocoglu, U., Akbulut, H.

(2014), Electrochemical performance of MWCNT rein-

forced ZnO anodes for Li-ion batteries, Microelectronic

Eng., 118, 54–60.

Huang, X.H., Xia, X.H., Yuan, Y.F., Zhou, F. (2011),

Porous ZnO nanosheets grown on copper substrates as

anodes for lithium ion batteries, Electrochim. Acta, 56,

4960-4965.

Ning, Y., Jianhua, W., Yuzhong, G., Xiaolong, Z. (2008),

SnO2 Nanofibers Prepared by Sol-Gel Template Method ,

Rare Metal Mater. Eng., 37, 694-696.

Wang, Y., Su, F., Lee, J.Y., Zhao, X.S. (2006), Crystalline

Carbon Hollow Spheres, Crystalline Carbon−SnO2 Hollow

Spheres, and Crystalline SnO2 Hollow Spheres: Synthesis

and Performance in Reversible Li-Ion Storage, Chem. Ma-

ter., 18, 1347-1353.

The Effect of Different Solvent Combination of LiBF4

Electrolyte on Free-Standing SnO2/MWCNT Nanocomposite

Anode Capacity for Li-ion Batteries

Ş. Karaal, H. Köse, A. O. Aydın, H. Akbulut

Sakarya University, 54187, Sakarya, Turkey

Abstract: Owing to their high energy density, lit-

hium-ion batteries are widely used in portable elect-

ronics (Xiang et al.; 2009). With a wide optical band

gap (3.6 eV) tin dioxide is an n-type semiconductor

material. For rechargeable lithium batteries, tin and

tin oxide based materials are being used as active

anode materials (Kose et al.; 2013). However, during

Li+

insertion/extraction cycles, anodes of such high

capacity usually suffer severe capacity fading result-

ing from both the huge volume change and the quick

aggregation of tin particles (Zhang et al.; 2009).

MWCNT buckypaper substrates are considered as a

buffer material during the battery applications in or-

der to prevent the pulverization of the anodes and

electrical detachment of active materials (Kose et al.;

2013). For commercial Li-ion cells, the typical non-

aqueous electrolyte is a solution of LiPF6 in linear

and cyclic carbonates such as dimethyl carbonate and

ethylene carbonate, respectively (Kerr et al.; 2003).

Compared with LiPF6, LiBF4 has some advantages

such as better thermal stability and lower sensitivity

toward environmental moisture and its solution pro-

vides lower charge-transfer resistance, especially at

low temperatures (Zhang et al.; 2006).In this work,

free-standing SnO2/MWCNT nanocomposite was

used as anode, metallic Li as cathode and 1 molal

LiBF4 solution as electrolyte. It was aimed to deter-

mine the optimum ratio of Ethylene Carbonate

(EC):Dimethyl Carbonate (DMC) solvents in 1 molal

LiBF4 electrolyte solutions for high capacity

SnO2/MWCNT buckypaper anode. Different EC :

DMC (2:1, 1:1 and 1:2) solvent combinations were

prepared in a glove box. For these electrolyte solu-

tions, conductivity tests were applied. Structural

properties and electrochemical performances of

SnO2/MWCNT nanocomposite anodes prepared by

sol–gel spin coating method (Figure 1) were investi-

gated. The structural properties of free-standing

buckypaper composite anode was characterized by

SEM (Scanning Electron microscopy), TEM (Trans-

mission Electron Microscopy) EDS (Energy Disper-

sive X-ray Spectroscopy) and XRD (X-ray Diffrac-

tion) tehcniques. Electrochemical performance tests,

CV (Cyclic Voltammetry) and EIS (Electrochemical

Impedance Spectroscopy) analyses of free-standing

anodes of CR2016 type Li-ion batteries were also

performed. The cells were charged and discharged at

25 °C between fixed voltage limits (2.5 V to 0.2 V).

Keywords: Li-ion battery applications, LiBF4 elec-

trolyte, ethylene carbonate, dimethyl carbonate,

SnO2/MWCNT nanocomposite anodes, sol-gel syn-

thesis, spin coating method, structural and electro-

chemical characterization.

MWCNT buckypapers

FEG-SEM Image

Figure 1: The representation of the production of

free-standing SnO2/MWCNT anodes.

References:

Kose, H., Aydin, A.O., Akbulut, H., (2013), Sol–gel prepa-

ration and electrochemical characterization of

SnO2/MWCNTs anode materials for Li-ion batteries, App-

lied Surface Science, 275, 160-167.

Sloop, S.E., Kerr, J.B., Kinoshita, K., (2003), The role of

Li-ion battery electrolyte reactivity in performance decline

and self-discharge, Journal of Power Sources, 119–121,

330-337.

Xiang, H.F., Wang, H., Chen, C.H., Ge, X.W., Guo, S.,

Sun, J.H., Hu, W.Q., (2009), Thermal stability of LiPF6-

based electrolyte and effect of contact with various delithi-

ated cathodes of Li-ion batteries, Journal of Power Sour-

ces, 191, 575–581.

Zhang, H.-X., Feng, C., Zhai, Y.-C., Jiang, K.-L., Li, Q.-

Q., Fan, S.-S., (2009), Cross-Stacked Carbon Nanotube

Sheets Uniformly Loaded with SnO2 Nanoparticles: A

Novel Binder-Free and High-Capacity Anode Material for

Lithium-Ion Batteries, Adv. Mater., 21, 2299-2304.

Zhang, S.S., Xu, K., Jow, T.R., (2006), Enhanced perfor-

mance of Li-ion cell with LiBF4-PC based electrolyte by

addition of small amount of LiBOB, Journal of Power

Sources, 156, 629-633.

SnO2 sol

Spin coater

Photocatalytic Activities of ZnO and ZnO/ZnS Synthesized by

Microwave-Hydrothermal Method

N. Güy,1*

Şeref Durmuş1, M. Özacar,

1

1Sakarya University, Department of Chemistry, Sakarya, Turkey

Abstract: Because of the diffussing of toxic and col-

oured wastewater into water sources, dyes have a bad

effect on the nature of water like inhibitting sunlight

penetration and reducing photosynthetic reaction.

(Hu et al.; 2011). The techniques which are used for

the treatment of dye waste effluents are usuallyare

usually inefficient, non-destructive and costly. (Jia et

al.; 2013). Heterogeneous semiconductor photocata-

lysts such as ZnO have an important role for the re-

moval of dye pollutants from water. ZnO semicon-

ductor has a wide bandgap energy of 3.37 eV and a

relatively large exciton binding Energy (60 meV),

thus can absorb only UV light with the wavelength

equal to or less than 385 nm. But solar spectra con-

tain only approximately 3%–5% UV light; therefore,

the great mass of solar photons is useless for ZnO

photocatalyst, which greatly limits its environmental

applications (Ma et al.; 2011). The photocatalytic

performance of ZnO can be improved by modifica-

tion due to inhibit recombination of photogenerated

electron-hole pairs. The band gap of ZnS (3.68 eV) is

larger than that of ZnO, experimental results have

demonstrated that the combination of these two wide

bandgap semiconductors could yield a novel compo-

site with the photo excitation threshold energy lower

than those of the individual components (Ma et al.;

2013). In the present study, ZnO/ZnS nano photo-

catalysts were synthesized by microwave-

hydrothermal method using different precursors as

Sulfur source. The prepared photocatalysts were

characterized by X-ray diffraction (XRD), field emis-

sion scanning electron microscopy (FESEM) and

UV–visible (UV–vis). The photocatalytic activities

samples and undoped ZnO have been studied for the

degradation of dye, and have also been compared

with together.

.

Keywords: Synthesis, photocatalyst, ZnO/ZnS, deg-

radation

Figure 1: Kubelka-Munk transformed reflectance

spectra of ZnO/ZnS

References:

Hu, Y., Qian, H., Liu, Y., Du, G., Zhang, F., Wang,

L., Hu, X.(2011), A microwave-assisted rapid route

to synthesize ZnO/ZnS core–Shell nanostructures via

controllable surface sulfidation of ZnO nanorods,

CrystEngComm., 13, 3438-3443.

Jia, W., Jia, B., Qu, F., Wu, X., (2013), Towards a

highly efficient simulated sunlight driven photoca-

talyst: a case of heterostructured ZnO/ZnS hybrid

structure, Dalton Trans., 42, 14178-14187.

Ma, H., Han, J., Fu, Y., Song, Y., Yu, C., Dong, X.,

(2011), Synthesis of visible light responsive ZnO–

ZnS/C photocatalyst by simple carbothermal reduc-

tion, Applied Catalysis B: Environmental 102, 417–

423.

Ma, H., Cheng, X., Ma, C., Dong, X., Zhang, X.,

Xue, M., Zhang, X., Fu, Y., (2013), Synthesis, Cha-

racterization, and Photocatalytic Activity of N-Doped

ZnO/ZnS Composites, International Journal of Pho-

toenergy, 2013, 8 pages.

Polystyrene  Micro/Nanofibers  and  its  Application  in  the  Removal  of  Crude  Oil  Spills  

M. Alazab Alnaqbi1,*, Afra Al Blooshi1, Yaser. Greish1, and Mahmoud Mohsin2

1Department of Chemistry, United Arab Emirates University, Al Ain, United Arab Emirates 2Department of Chemistry, University of Sharjah, Sharjah, United Arab Emirates

Abstract: Water pollution by crude oil has major environmental impact worldwide (M. Al-Azab et al. 2005). The great concern of the global community on the unfavorable and longstanding effects of spilt oil on ecosystems, created a vital need to develop materials for effective oil spill clean-ups (Xia, Y. Q et al. 2010). This work aimed to study the effective-ness and applications of PS polymer in clean-up of crude oil from oil spills. Molecular weights of the fibrous polystyrene precur-sors, were in the range of 100,000 – 350,000 Dalton. Fibers were used for the removal of crude oil spills in seawater. Due to the hydrophobic nature of both the fibers and the crude oil, the later was instantly ab-sorbed onto the fibers achieving a maximum sorption capacity of 220 g of crude oil per each gram of fiber. Nano/Microfibers of polystyrene was prepared by electrospinning technique (Haitao Zhu et al. 2011). Fibers with a size range of 500 nm- 8 µm in diameter and below 100 m2/g in surface area were prepared after a thorough optimization of the electrospinning process. Fibers prepared were tested for their oil absorption efficiency as a function of absorbent weight, time of absorption, and initial concentration of the polymer solution prior its conversion to fibers. Results showed an initial sorption capacity of a range of 60-200 g/g with microfibers prepared from 20% PS solution. The surface area of the produced fibers varied based on fiber size distribution, which depends on varia-tions in the electrospinning parameters. Hence, opti-mizations of the process were studied to achieve con-sistency in the fiber size distribution, and the surface area of the fibers as well. Results showed the im-portance of the high surface area and interconnectivi-ty of the porosities within the PS microfibrous sorbent for the removal of the oil, making the micro-fibrous PS sorbents an excellent candidate for crude oil spill cleanup. Keywords: nanofibers, polystyrene, crude oil, elec-trospinning

Figure 1: SEM image for electrospun PS fibers with mesoporosity and different size distribution. Poly-styrene was dissolved in the proper solvent forming solutions of 20, 30, and 40 wt%. Electrospinning process conditions were optimized at a voltage of 20 kV, a feeding rate of 10 ml/hr, and a distance of 15 cm. Due to the high viscosity of the crude oil, their flow within the fibrous sorbent during the process of removal will be limited and requires macroporosity for a more efficient sorption and impregnation within the fibrous sorbent. The produced microfibers con-tained macroporosity by virtue of the interlocking between the fibers within the electrospun fibrous mesh.

References: M. Al-Azab, E. El-Shorbagy and S. Al-Ghais (2005). Proceedings of the International Conference on "Oil Pollution and it Environmental Impact in the Arabian Gulf Region". Elsevier, ISBN: 978-0-444-52060-9. Xia, Y. Q.; Boufadel, M. C. (2010) Lessons from the Exxon Valdez oil spill disaster in Alaska. Disaster Adv, 3 (4), 270−273

Haitao Zhu, Shanshan Qiu, Wei Jiang, Daxiong Wu, and Canying Zhang (2011), Evaluation of Electro-spun Polyvinyl Chloride/Polystyrene Fibers As Sorbent Materials for Oil Spill Cleanup, Environ. Sci. Technol, 45, 4527–4531

Effects of biopolymer nano coils on sand dune stabilization and dust

controlling

M. Aghaei Moghadam1*, K. Zangeneh2 1 Biopolynet Inc, Fredericton, NB, Canada

2 Biopolynet Inc, Fredericton, NB, Canada

*Email: mostafa@biopolynet.com

Abstract

Despite the large history and popularity of sand/dune stabilization in exploratory research, a unique

method with large-scale applications has yet to be realized. The main impediments reside in the

methods of the stabilizations currently in use, at the moment (a) no specific technology is available,

(b) a particular stabilizer is necessary for each specific condition, (c) most products just stabilize the

surface of sand dunes and (d) most applications require a long time to be fixed in large quantities

in a predetermined and controllable fashion. Designing biopolymeric networks with controlled

size and desirable properties is the best way to fix sand dune and dust. Thus we hereby describe a

novel view and simple method to stabilize sand/dunes by designing a novel aqueous biopolymer

coils system to spray on the sand/dune surface in order to make a network with sand/dune agents

by penetration of aqueous biopolymer into the sand dune.

Carboxymethyl-nanocellulose:a versatile raw-material in coating industry

A. Reis,

1,* R. Duarte,

1 J. Tedim,

2 A. Caetano,

2 A.P. Mendes de Sousa,

3 J. Ataíde,

3 D. Evtuguin

1

1CICECO-Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Portugal

2CICECO-Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Avei-

ro, 3810-193 Portugal 3RAIZ, grupo PORTUCEL/SOPORCEL, 3801-501 Eixo, Portugal

Abstract: Cellulose is the most abundant polysac-

charide and widespread biopolymer in nature. For

this reason, cellulose and its derivatives are very at-

tractive for the manufacture of sustainable biobased

materials. Unlike cellulose, functionalized cellulose

with carboxymethyl groups (CMC) is water soluble

exhibiting a multitude of applications as gelling agent

in food industry, as paint thickeners in coating indus-

try and film packaging in food and paper industry

(Klemm et al., 2005). Aside from its mechanical and

water retention properties, the biocompatibility ex-

hibited makes CMC a promising option as a support

of biomolecules with chemical and biological activity

for the development of biosensors and wound dress-

ings (Carlsson et al., 2014). However, commercially

available CMC powders have high degrees of substi-

tution (DS) ranging between 0.5-1.2 and a high den-

sity of anionic charged groups by the presence of

surface carboxylic groups. The high surface negative

charge has a deleterious impact on the stability of the

incorporated biomolecules (Carlsson et al., 2014) and

even affecting the release behavior of incorporated

drug (Valo et al., 2013).

In this study, we have synthetized CMC with various

degrees of substitution (DS) using environment-

friendly aqueous conditions. The functionalized

CMC pulp with DS<0.2 was submitted to ultraho-

mogenization resulting in high quality carboxymethyl

nanocellulose (NC) suspensions (over 90% of nano-

fibrils) through a energy-efficient process(energy

reduction of >60% compared to unmodified NC).

The carboxymethyl-NC films prepared by solvent

casting exhibited improved optical and morphologi-

cal properties whilst retaining the mechanical proper-

ties in the temperature range (-50 to 200C) studied.

Preliminary results obtained by electrochemical im-

pedance spectroscopy (EIS) using functionalized

nanocellulose in solution and as additives to protec-

tive coatings have shown improved anti-corrosion

performance in coated substrates. The increased hy-

drophobicity and zeta potential of prepared CMC

suspensions reveal great potential for industrial coat-

ing and will be further explored on the adsorption of

molecules for biomedicine applications.

Keywords: carboxymethyl cellulose, transparent

films, corrosion inhibitors, biomedical applications.

References:

Klemm, D., Heublein, B., Fink, H.P., Bohn, A.

(2005) Cellulose: fascinating biopolymer and sus-

tainable raw material, Angew. Chem. Int., 44, 3358-

3393.

Valo, H., Arola, S., Laaksonen, P., Torkkeli, M.,

Peltonen, L., Linder, M.B., Serimaa, R., Kuga, S.,

Hirvonen, J., Laaksonen, T. (2013), Drug release

from nanoparticles embedded in four different nano-

fibrilar cellulose aerogels, Eur. J. Pharm Sci., 50, 69-

77.

Carlsson, D.O., Hua, K., Forsgren, J., Mihranyan, A.

(2014), Aspirin degradation in surface-charged

TEMPO-oxidized mesoporous crystalline nanocellu-

lose. Int. J. Pharma. 461, 74-81.

Acknowledgements

This work was developed in CICECO-Aveiro Insti-

tute of Materials and is funded by ERDF Funds

through Operational Competitiveness Programme –

COMPETE in the frame of the project NMC– QREN

34169.

Graphene Reinforced Concrete

M.F. Craciun, D. Dimov

University of Exeter, Exeter, Devon, United Kingdom

Abstract:

This work presents the revolutionary idea of bridg-

ing the international research on nanoscience with

traditional construction material concrete. The aim

of the project is to introduce graphene - an one at-

om thick layer of graphite with two-dimensional

properties, within the chemical matrix of cement.

The stand-out mechanical properties of graphene

such as very high ultimate tensile strength and re-

taining initial size after strain make it suitable for

applications in the construction industry. There are

two main liquid exfoliation methods of producing

surfactant-stabilized graphene dispersions in aque-

ous environment [2],[3]. The first one uses soni-

cation energy principles for breaking down layers of

graphite and the addition of surfactant (Sodium

Cholate) preserves all of their properties in water

[3]. The second uses high-shear exfoliation machine

which uses laws of turbulent forces to achieve even

better quaility flakes with more consistent rate of

dispersion [2]. The resultant solution from 48h of

sonication is mixed with Ordinary Portland Cement

(OPC), sand and aggregate to prepare standard

10x10x10cm concrete cubes for testing compres-

sive strength. The results show that the addition of

only 2.1mg/ml of graphene flakes increase the com-

pressive strength by 9.8% when compared to cubes

mixed with normal tap water, after 28days of curing

time. The outcomes of the experiments prove the

hypothesis that wonder nanomaterial alter the hy-

dration crystals of the cementitious paste and the

enhanced hydration reaction in the curing period of

the concrete leads to many improvements [1]. The

graphene reinforced concrete can revolutionize the

construction industry and change the face of future

infrastructure by introducing a very environmental

friendly product.

Keywords: graphene, concrete, liquid exfoliation,

cement, hydration reaction, compressive strength

Figure 1: Two cubes above show the comparison

between normal (tap water) concrete on the left and

graphene reinforced one on the right. The addition

of nanomaterials enhances the main chemical reac-

tion during the hardening of concrete and this leads

to increased compressive strength of the construc-

tion material.

References:

[1] A. Sedaghat, M. K.Ram, A. Zayed, R. Kamal,

N. Shanahan, “Investigation of Physical Prop-

erties of Graphene-Cement Composite for

Structural Applications,” Open Journal of

Composite Materials, 2014, 4, 12-21

[2] K. P. Paton, “Scalable production of large

quantities of defect-free few-layer graphene by

shear exfoliation in liquids”, Nature Materi-

als, April 2014, 10.1038/NMAT3944

[3] M. Lotya, P. J. King, U. Khan, S. De, J. N.

Coleman, “High-Concentration, Surfactant-

Stabilized Graphene Dispersions”, ACSNano,

2010, Vol.4, No.6, 3155-3162

Quantum Dot Sensitized Solar Cells with Cuprous Sulfide Counter Electrode

Nuno Marques Ferreira, César Bernardo, Isabel Moura, Paulo J. G. Coutinho, Anabela G. Rolo, Mikhail Vasi-

levskiy, M. Pastor, F. Fernandes, V. Teixeira, J.O.Carneiro, Anura Samantilleke*

Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal

Abstract: Although, solution processing is a promis-

ing route for the realization of low-cost, large-area

devices with short energy payback time and high spe-

cific power, low-temperature fabrication conditions

and good atmospheric stability while maintaining a

high efficiency remains a major technical challenge.

However, the recent report of a certified efficiency of

8.55% for a ZnO/PbS Quantum dot (QD) solar cell

(SC) achieved by engineering the band alignment of

the QD layers through the use of different ligand

treatments promises the possibility of newapproaches

towards the goal of high-performance air-stable solar

cells compatible with simple solution processes (Chuang et al, 2014). CdSe QDs with an absorption onset in the red or near infrared are equally promis-ing (Kamat, 2008). In this work, QDSCs based on a

mesoporous structure of TiO2 and a polysulfide re-

dox electrolyte, were prepared by adsorption of col-loidal CdSe QD absorbers onto the photoanode, with and without linkers. CdSe/ZnS QDs were synthesized within aqueous pools of reverse micelles, based on standard wet chemistry methods, while al-kylphosphine oxide (TOPO) functionalized CdSe QDs were prepared by reactions of organo-metallic pre-cursors at high temperature. A chlorine surface treatment performed on TiO2 prior to sensitisation improved QD adsorption on the photoanode. An electrochemically deposited Cu2S/conducting glass (CTO), which has a higher tolerance to polysulfide electrolyte, was used as the counter electrode. The Cu2S film, composed of interconnected nanoflakes, showed good catalytic activity with the best SCs (ef-fective area 0.16 cm2) showing up to 2.13% conver-sion efficiency under AM1.5 illumination. The pho-tovoltaic characteristic of the solar cells was meas-ured using a calibrated solar simulator with 100 mW/cm2 irradiation (AM 1.5). The colloidal QDSC performance was primarily limited by a low fill factor of 0.45, which is believed to arise from charge trans-fer of photogenerated electrons to the aqueous electrolyte. This work was supported by the MATEPRO - NORTE-07-0124-FEDER-000037 and the European Commission through NanoCIS project (FP7/PIRSESGA-2010-269279), both of which are gratefully acknowledged.

Keywords: CdSe, quantum dot, solar cell, TOPO,

Cu2S

Presenting author’s email: anura@fisica.uminho.pt

Figure 1: Ressonance Raman spectrum of CdSe na-

noparticles (NP) deposited on glass, excited at laser

wavelength 514 nm. (1)-TO (170.3 cm-1); (2)-LO

(204.7 cm-1); (3)-2LO (408.8 cm-1).

Laser intensity of <9.32 kW/cm2 was used to mini-

mize a possible local heating. Red and green depict

the spectral deconvolution to the vibrational modes.

The inset shows the amplified Raman shift' at (3).

LO phonon mode shift and asymmetric broadenings

towards low-frequency (2,3) in comparision with

Bulk CdSe are explained by the contribution of dif-

ferent phonon modes and are an indication of the

phonon confinement effect, which is a consequence

of the nano size of the CdSe particles. The presence

of transverse modes at (1) is an evidence of the non

spherical symmetry of the NP's.

References:

[1]..Prashant V. Kamat, (2008) Quantum Dot Solar

Cells. Semiconductor Nanocrystals as Light Harvest-

ers, J. Phys. Chem. C, 112 (48), 18737–18753

[3]. Chia-Hao M. Chuang, Patrick R. Brown, Vladi-

mir Bulović and Moungi G. Bawendi (2014) Im-

proved performance and stability in quantum dot

solar cells through band alignment engineering, Na-

ture Materials, 13,796–801

Reduced graphene oxide on TiO2 nanorods and nanotubes photo-

anode for solar hydrogen evolution

Hyun Kim,1 Bee Lyong Yang1*

1Kumoh National Institute of Technology, Laboratory of nanoelectric materials, Geongbuk, Korea

Abstract: The solar hydrogen evolution process via

water splitting is a carbon free technology for next

generation. Many reseachers and energy departments

are expecting that minimum efficiency for

commercialization is about ~10% of solar to

hydrogen conversion efficiency (STH). However the

world STH efficiency doesn't reach yet. Splitting

water into hydrogen and oxygen has been occured by

stages, i) absorption of light, ii) electron-hole excita-

tion, iii) charge transfer to reactive sites, iv) redox

reaction. Among these stages, charge transfer stage is

most important to lead the redox reaction of water.

Graphene has been considered a new approach to

improve the charge transfer rate without direct or

indirect recombination. In this work, we

demonstrated that improved charge transfer and

collection in PEC system by using a reduced

graphene oxide sheets. Reduced graphene oxide

sheets were chemically synthesized by improved

Hummer’s method. TiO2 nanotubes and nanorods

were synthesized by anodizing and hydrothermal

method respectively. Subsequently, These TiO2 pho-

to-anodes were directly immersed into solution in-

volving reduced graphene oxide. After several

minutes in immersed state, the graphene oxide on

TiO2 nanotubes were chemically reduced by adding

hydrazine solution as a reducing agent. The micro-

structural features of RGO/TiO2 nanotubes photo-

anode were investigated by FE-SEM, TEM, XRD,

Raman spectroscopy. Furthermore solar hydrogen

production test was characterized in the PEC cells

Consequently graphene decorated TiO2 nanotubes

and nanorods were revealed superior photocatalytic

activity because the graphene sheets led to increase

the mobility of charge carriers and recombination

time.

Keywords: Reduced graphene oxide(RGO), Titani-

um dioxide(TiO2), Solar hydrogen evolution

Figure 1: FE-SEM image of a graphene oxide coated

TiO2 nanorods.

References:

Ma, Y., Wang, X., Jia, Y., Chen, X., Han, H., Li, C.

(2014) Titanium dioxide-based nanomaterials for

photocatalytic fuel generations, Chem. Rev., 114,

9987-10043.

Te-Fu, Y., Jaroslav, C., Chih-Yung, C., Ching, C.,

Hsisheng, T. (2013) Roles of graphene oxide in pho-

tocatalytic water splitting, Mater. Today., 16, 78-84.

Daniela C, M., Dmitry V, K., Jacob M, B., Alexander,

S., Zhengzong, S., Alexander, S., Lawrence B, A.,

Wei, L., James M, T. (2010) Improved synthesis of

graphene oxide, ACS. NANO., 4, 4806-4814.

Silicon Nanowire as an Effective Absorber for Solar Cell Application: Fabrication and Numerical Simulation

M. K. Hossain,1,* B. Salhi,1,* A. W. Mukhaimer,1 and F. A. Al-Sulaiman1,2

1Center of Research Excellence in Renewable Energy (CORERE), King Fahd University of Petroleum and Min-erals (KFUPM), Dhahran 31261, Dhahran, Kingdom of Saudi Arabia

2Departmentof Mchnical Engineering, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Dhahran, Kingdom of Saudi Arabia

Abstract: Silicon nanowires (Si-NWs) have been considered widely as a perfect light absorber with strong evidence of enhanced optical functionalities. Here we report finite-difference time-domain simula-tions for Si-NWs to elucidate the key factors that determine enhanced light absorption, energy flow behavior, electric field profile and exciton generation rate distribution. To avoid further complexity, a sin-gle Si-NW of cylindrical shape was modelled on c-Si and optimized to elucidate the aforementioned char-acteristics. Light absorption and energy flow distri-bution confirmed that Si-NW facilitates to confine photon absorption of several orders of enhancement whereas the energy flow is also distributed along the wire itself. With reference to electric field and exci-ton generation distribution it was revealed that Si-NW possesses the sites of strongest field distribu-tions compared to those of flat silicon wafer. To real-ize the potential of Si-NWs-based thin film solar cell, a simple process was adopted to acquire vertically aligned Si-NWs grown on c-Si wafer. Further topo-graphic characterizations were conducted through SEM and TEM-coupled EDS. Keywords: Fabrication, FDTD simulation, photo-voltaic solar cell, Silicon nanowires. One dimensional Si nanostructures, such as, Si nan-owires (Si-NWs) have been emerged as an extremely

(a)

(c)

(b)

(d)

Electric field Generation rate

Fig. 1 Electric field and generation rate profile at 740

nm wavelength. (a) Fabry-Perot mode like electric field distribution in c-Si slab, (b) generation rate distribution in c-Si slab, (c) confined and enhanced electric field distribu-tion in Si-NW on c-Si slab and (d) confined exciton gener-

ation rate distribution along the Si-NW length.

attractive candidate due to their unique properties. Apart from low-cost, Si-NWs have strong optical absorption in the solar spectrum, i.e., less than 1% equivalent of Si materials in Si-NWs can achieve the same amount of absorption absorbed by traditional planar wafer-based PV devices. Si-NWs-based solar cells with radial p-n junctions offer a short collection length for charge carriers, thus allowing the use of lower-quality Si materials. Si-NWs can be produced with excellent electrical characteristics. These ad-vantages may substantially reduce the production cost of Si-NW-based solar cells while retaining effi-ciencies competitive with planar multicrystalline Si solar cells. Vertically aligned Si-NWs were fabricated on c-Si wafer. The process was consisted of four simple steps, viz. i) ultrathin layer of Au coating on c-Si wafer, ii) sintering to turn the film into Au nanopar-ticles, ii) CVD to grow Au nanoparticles-assisted Si-NWs and iv) removal of Au nanoparticles. SEM and TEM measurements confirmed a variety of lengths (eg. few microns) and diameters (eg. 50 to 200 nm) of Si-NWs.

(a) (b)

(d)(c)

Fig. 2 SEM micrographs. (a) wide view of as-fabricated Si-

NWs on c-Si wafer, (b) close-view of individual as-fabricated Si-NWs showing different dimensions in length

and diameter, (c) Magnified images of the small area marked by white square in Fig. 2a and (d) TEM-coupled

EDS to confirm the elemental composition of as-fabricated Si-NWs on c-Si wafer.

Details will be presented and explained in full report. Acknowledgement: The authors are thankful to Cen-ter of Research Excellence in Renewable Energy (CoRERE), King Fahd University of Petroleum and Minerals, KSA.

Environmentally Friendly Design of Tailor-Made Nano-porous Polymeric Gas

Adsorbents

Worood A. El-Mehalmey*, 1

Tarek Madkour1

and Rasha A. Azzam2

1Department of Chemistry, The American University in Cairo, New Cairo, Egypt

2Department of Chemistry, Helwan University, Ain-Helwan, Cairo, Egypt

Abstract: More than 80% of the worldwide commercial

energy supply is based on fossil fuels. The heavy use of

fossil fuels as energy source has led to two major drawbacks.

The first is environmentally related problem due to the large

amounts of greenhouse gas (GHG) emissions, especially

carbon dioxide (CO2) whereas the second problem is related

to the continual depletion of the fossil fuel resources.

Eliminating the dependency on fossil fuel as a source of

energy and searching for alternative sources for energy use

such as hydrogen is, therefore, a crucial step.

Conventionally, gases of a natural gas mix are separated

using cryogenic distillation, which is an energy intensive

process as well as a damaging one to the environment since

it involves the consumption of large amount of fossil fuel to

generate the required energy for the liquefaction and

distillation processes. Hence, there is an urgent need for gas

separation using a novel cost-effective material that

consumes lower energy.(McKeown, Budd, & Book, 2007;

Xu et al., 2014) A range of nanoporous polyimide polymers

were synthesized using a two-step poly-condensation

reactions as shown in Figure 1 of bis (carboxylic anhydride)

with various aromatic diamines designed to investigate their

effect on both the pore sizes and pore size distribution for

gas storage application. This reaction ended with the

formation of polymers of intrinsic micro-porosity (PIM),

which are known to comprise rigid backbone due to their

lack of rotational freedom along the polymeric

backbone.(McKeown & Budd, 2010) The polymers

exhibited high surface area as determined by nitrogen

adsorption and high thermal stability as determined by TGA.

The high surface area was further validated using molecular

simulation techniques. Structural modifications of the

diamines have resulted into a variety of nano-porous

polymeric structures. The chemical structures were

confirmed using FTIR, NMR and GPC techniques. BET

isotherms of the resultant polymers were carried out to

evaluate their physical characteristics. The results showed

that the fractional free volume and the Connolly surface of

the PIMs had greater values resulting from the inability of

the rigid and contorted structures of the PIMs to pack space

efficiently and thus creating interconnected nano-channels

throughout the polymeric structures as shown in Figure 2.

Keywords: Carbon dioxide, Hydrogen, Polymers of

Intrinsic Micro-porosity (PIMs), Two-step poly-

condensation, interconnected nano-channels, gas adsorbents.

Figure 1 Synthesis of Nano-Porous Polyimide using Two-

Step Poly-condensation.

Figure 2 PIM-004-PI Porous Structure.

References:

McKeown, N. B., & Budd, P. M. (2010). Exploitation of intrinsic microporosity in polymer-based materials. Macromolecules,43,5163–5176. doi:10.1021/ma1006396

McKeown, N. B., Budd, P. M., & Book, D. (2007). Microporous polymers as potential hydrogen storage materials. Macromolecular Rapid Communications, 28, 995–1002. doi:10.1002/marc.200700054

Xu, G., Liang, F., Yang, Y., Hu, Y., Zhang, K., & Liu, W.

(2014). An improved CO2 separation and purification

system based on cryogenic separation and distillation theory.

Energies, 7, 3484–3502. doi:10.3390/en7053484

Silica-based nanocoating and LDHs sensors for enhancement of paperboard barrier properties

V. M. Dias1*, A. Kuznetsova2, I. Portugal1, J. Tedim2, A. A. Yaremchenko2, D. V. Evtuguin1

1CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Aveiro, Portugal 2CICECO - Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, Aveiro,

Portugal *e-mail: vania.dias09@gmail.com

Abstract: Conventional solutions to enhance paper-board barrier properties for packaging are limited essentially to film coating by synthetic polymers that hinder end-of-life disposal or recycling (Han et al., 2010). Sol-gel methods are proven and convenient for organic-silica nanocoating since silica particles are generated in situ and randomly dispersed on the paper surface thus forming an impermeable interface between three-dimensional silica network and cellu-lose fibers (Han et al., 2010; Sequeira et al., 2007) Tetraethyl orthosilicate (TEOS) is often used as silica precursor, individually or mixed with other alkoxid-ederived precursors. For instance, dimethyldiethox-ysilane (DEDMS), 3-aminopropyltriethoxysilane (APTES) and octyltriethoxysilane (OTES) can be used to improve barrier properties due to their polari-ty. Similarly, Zn(2)-Al-NO3 type layered double hydroxides (LDHs) can be added to the formulation and used as anion/water sensors (Tedim et al., 2011). The silica-coated paperboard were characterized by scanning electron microscopy (SEM-EDS). Water vapor transmission rate (WVTR) was measured by the “desiccant method” (ASTM E 96-95, 1995) and oxygen permeation (���) measurements were per-formed using air in one side of paperboard and nitro-gen flow on the other side and measuring p(O2) in the N2 flow (Yaremchenko et al., 2007). Keywords: Nanocoating, paperboard, silica-based formulations, layered double hydroxides, sol-gel process, barrier properties. SEM images (Figure 1) of paperboard transversal cuts (delimited by dashed lines) reveal the position of silicon (red areas) on the side where the formulation was applied (ca. 2 g/m2). Silica (red color) remains mostly at the outer surface.

Figure 1: SEM image of TEOS_OTES formulation (2g/m2) applied on the paperboard surface (left side).

Table 1. Barrier properties of paperboard before (uncoated) and after coating with various silica based formulations.

WVTR

(g m-2 day-1) ���

(m3 m-2 day-1) Uncoated 548.83 ± 21.05 1.512

TEOS 300.20 ± 4.87 0.677

TEOS_LDHs 269.59 ± 3.25 1.037

TEOS_DEDMS 230.98 ± 3.33 0.562

TEOS_DEDMS_LDHs 199.25 ± 2.98 0.936

TEOS_APTES 221.96 ± 4.04 0.490

TEOS_APTES_LDHs 132.35 ± 2.95 0.778

TEOS_OTES 225.60 ± 3.54 2.578

TEOS_OTES_LDHs 131.37 ± 2.90 1.915

Generaly the incorporation of a secondary silica precursor improves barrier properties (WVTR and ��� decrease) (Table 1). For example, in comparison with the uncoated the TEOS_APTES coating de-creased WVTR approximately 60% and ��� about 67%. The incorporation of LDHs caused an increase in ��� (ca. 60%) and diminished WVTR (ca. 10-40%) when compared with initial formulations. The best results were obtained with the formulation TEOS_APTES. Considering the anionexchange properties of LDHs they can act as nanosensors but also as water scavengers. Conclusion: Silica coated paperboards exhibit good barrier properties when mixed silica alkoxide precur-sors are used. The incorporation of LDHs is very promising. References: Han, J., Salmieri, S., Le Tien, C., Lacroix, M. (2010), J. Agric. Food Chem., 58, 3125–3131. Sequeira, S., Evtuguin, D. V., Portugal, I., Esculcas, A. P. (2007), Mater. Sci. Eng. C, 27, 172–179. Tedim, J., Kuznetsova, A., Salak, A. N., Montemor,F., Snihirova, D., Pilz, M., Zheludkevich, M. L., Ferreira, M.G.S. (2011), Corros Sci, 55, 1-4. ASTM E 96-95, (1995) Annual Books of ASTM Stand-ards, 552, 785–792. Yaremchenko, A. A., Kharton, V. V., Avdeev, M., Shaula, A. L., Marques, F. M. B. (2007). Solid State Ionics 178, 1205–1217.

This work was developed in the scope of the project CICECO-Aveiro Institute of Materials (Ref. FCT UID /CTM /50011/2013), financed by EU funds of FP7 pro-gram (FP7-NMP-2011-LARGE-5 - NanoBarrier). Authors also thank the Prado Karton SA for the paperboard sub-strates.